There are several kinds of hose clamps on the market. Some are adjustable in size except for very small tubing. Examples are U.S. Pat. Nos. 5,630,255 (Eliason); 4,638,531 (Ribrant); and 4,103,399 (Oetiker).
Rubber bands may sometimes used to secure, for example, a bag over the end of a tube. This is only practical when the tube is short or the bag is very small, since the rubber band must be looped, usually repeatedly, over one part or the other.